Anti-disturbance fuze

ABSTRACT

This invention relates to an anti-disturbance fuze capable of aerial dispersion for detecting the presence of intruders having a housing means, an arming delay means operatively positioned in the housing means for holding the fuze in a safe mode during dispersal, a pendulous inertial mass held in cantilever fashion as a disturbance sensing means proximate to the arming delay for detecting impulses to the fuze, and a firing means operatively connected to the sensing means for firing of an integral detonator. The fuze is immersed in a fluoro-carbon liquid during the dispersal stage and is held in a safe mode by the arming delay means. Upon evaporation of the fluorocarbon liquid the arming delay, after a short interval, of time actuates the disturbance sensing means, the latter is then sensitive to subsequent impulses or movements of the device and operates a biased firing mechanism to cause a detonation.

United States Patent 1 1 Primary Examiner-Samuel W. Engle Att0rneyHarry M. Saragovitz et al.

Mellen Sept. 18, 1973 ANTI-DISTURBANCE FUZE [75] Inventor: George P. Mellen, Wayzata, Minn. [57] ABSTRACT [73] Assignee: The United States of America as represented the Secretary of the This invention relates to an anti-disturbance fuze Army washmgtoni capable of aerial dispersion for detecting the presence [22] Filed; Jam 21, 1972 of intruders having a housing means, an arming delay means operatively positioned in the housing means for PP' N04 219,620 holding the fuze in a safe mode during dispersal, a v pendulous inertial mass held in cantilever fashion as a 52 Us. (:1 102/8, 102/70 R, 102/81 disturbance Sensing means proximate to the arming s11 Int. Cl. F42b 23/26 delay for detecting impulses the fuze, and a firing [58] Field 61 Search 102/8, 82, 70, 83, means Operatively connected t0 the sensing means for 102/16, 81 firing of an integral detonator. The fuze is immersed in a fluoro-carbon liquid during the dispersal stage and is 5 References Cited held in a safe mode by the arming delay means. Upon UNITED STATES PATENTS evaporation of the fluorocarbon liquid the arming 1 delay, after a short interval, of time actuates the S x disturbance sensing means, the latter is then sensitive 3'254602 6/1966 Klzsterhiianii etalx: 21.... 102/8 subsequem impulses 9' mvemems. device and 213751522 5/1945 Campbell 102/8 Pemes a mechamsm cause a detonation.

5 Claims, 8 Drawing Figures PATENIEnsm 81975 sum 2 0F 3 ANTI-DISTURBANCE IFIJZIE BACKGROUND OF THE INVENTION Various mechanical, chemical and electrical means have been used in anti-disturbance devices to actuate a mechanism which will sound a warning and/or cause a detonation whenever the mechanism is moved by an intruder. Some of the prior art devices utilize either the linear acceleration and/or the angular acceleration of the carrier to change the anti-disturbance device from a safe mode or position to an armed position, and a vibratory or flexing characteristic of a spring and mass combination to effect an electrical switch closure in order to change the anti-disturbance device to the fire mode or position. Other prior art devices use an electronic and/or mechanical delay in safe and arm mode and then use the free rolling motion of a ball to contact a post to affect the closure of an electrical circuit in the firing mode. The aforementioned types of antidisturbance devices prevent premature activation during delivery to the intended target area, however, they generally require the use of an expensive mechanical delay arming means in combination with complex electric or electronic timers. Normally in aerial mining it is desirable to have an anti-disturbance device which is both safe to handle and functionally inoperative during the dispersal stage and subsequently after dispersal to become reliably operative when subjected to movement by an unwanted intruder. It is also important that an anti-disturbance device should be insensitive to normal battlefield conditions such as rain, wind and sonic booms. Another desirable feature of an antidisturbance device is that it be relatively small so that it can be easily camouflaged, and relatively cheap to manufacture because of the large numbers needed to cover a battle area. The aforementioned mechanicalelectrical anti-disturbance devices are sometimes not reliable and are subject to premature firing and ma]- function because of exposure to spurious electric or nuclear radiating fields.

The prior art mechanical-electrical anti-disturbance devices and completely electrical devices are generally less reliable over long time periods because of the dependency upon a relatively short-lived battery. Prior art anti-disturbance devices which are operative solely by mechanical means of the frictional release type using balanced lever members are generally unreliable because they will respond either to environmental changes or to a specific act of an intruder.

The present device provides an all mechanical antidisturbance device which is safe to handle during the dispersal stages, self-arming after dispersal and insensitive to normal battlefield disturbance such as sonic boom, heat, rain and high electrical and nuclear radiations. The present device is also operatively reliable over long periods of time because of its independence from an electrical energy source of power.

SUMMARY OF THE INVENTION The present device consists of a FREON actuated arming delay, a disturbance sensing means and a firing pin triggering means which can be actuated by the sensing means when a sudden impact is imparted to the device when it is in an armed position. The present invention is an all mechanical device. During the safe mode a FREON expanded O ring is used to hold a slidable, non-rotatable, clutch member against a rotatable spring biased cam rotor so that the latter will restrain a counterweight triggering means from unlocking a spring-loaded firing pin when the device is either roughly handled or subjected to sudden impact. The arming delay mode utilizes the principle that silicone rubber will increase in volume when immersed in a fluorocarbon liquid, such as FREON, and then will return to its natural size and shape in a short interval of time, such as twenty minutes, upon removal from or evaporation of the fluorocarbon liquid. After the aforementioned delay, the device is placed in an armed position by the shrinking of the O ring thereby permitting the slidable clutch to move away from the biased cam rotor and freeing the latter to rotate to a second armed position which carefully balances the counterweight triggering means so that it will be sensitive to any significant battlefield disturbance. The cam rotor in the armed position also holds the biased firing pin means so that it is restrained from impacting upon an adjacent integral detonator. Any significant movement of the device after it is placed in the armed mode will cause the counterweight triggering means to release the biased cam rotor so that it can further rotate and thereby release the spring loaded firing pin.

One of the objects of this invention is to provide an all mechanical anti-disturbance device.

Another object of this invention is to provide an antidisturbance device which is not dependent upon electric circuitry for operation.

Another object of this invention is to insure reliable operation of an anti-disturbance fuze after long periods of shelf life.

Another object of this invention is to provide an antidisturbance device which does not require a battery for a power source.

Another object of this invention is to provide an antidisturbance fuze having an arming delay which is dependent upon the volumetric changes occurring to silicone rubber in the presence of a fluro-carbon liquid.

Another object of this invention is to provide an antidisturbance fuze which because of simplicity of design and few component parts is small in size, light in weight, economical to manufacture and reliable in operation.

For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan and partial cross-sectional view of the antidisturbance device showing the device in its safe position.

FIG. 2 is a cross-sectional view of FIG. 1 taken along line 2-2.

FIG. 3 is a plan and partial cross-sectional view of the antidisturbance device showing the device in its armed position.

FIG. 4 is a cross-sectional view of FIG. 3 taken along line 4 4.

FIG. 5 is a plan and partial cross-sectional view of the antidisturbance device showing the device in its fixed position.

FIG. 6 is a cross-sectional view of FIG. 5 taken along line 6-6.

FIG. 7 is a cross-sectional view of device shown in FIG. 2 taken along line 7-7.

FIG. 8 is a side view of the FIG. 7 taken along line 88.

Throughout the following description like reference numerals are used to denote like parts in the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2 when the present device is immersed in a FREON environment such that the base 10 has its base cavity 13 filled with this fluorocar bon liquid, the O ring 300 expands against the clutch 200 forcing it to slidably move on the base clutch holding boss 15, through clutch hole 201, so that the clutch 200 is firmly pressed against rotor 90. In so doing, the clutch teeth 202, on the upper surface of the clutch 200, mesh with the rotor teeth 91 located on the bottom surface of rotor 90. Since the clutch 200 is mounted on a squared shaft, herein called the base clutch holding boss 15, neither the clutch 200 nor the rotor 90 can rotate. In this position the fuze can neither arm nor fire, this position is therefore called the safe position. In the safe position a firing pin lock 40 has a pivot shaft 42 rotatably held on one side in the base pin lock pivot point bore 14 and on the other side by the base cover pin lock pivot point bore 22. The cantilever firing pin lock arm 41 is forcibly held against rotor 92 by the firing pin 50 and the compressed firing pin spring 60. The firing pin point 51 is held in this spring loaded position by the firing pin lock D" surface 43. A firing pin plug 52 is held in the base firing pin bore 12 by the firing pin plug stake 53, the plug 52 holds the firing pin spring 60 firmly against the firing pin 50.

In the safe mode the pendulous inertial mass counterweight 100 is held by the counterweight spring 102 so that the counterweight hook cam contact surface 101 does not engage the rotor arming cam projection 94. The counterweight spring 102 is of such diameter and length that regardless of the way the fuze may land after dispersal, the counterweight spring assembly will always return to the safe position shown on FIG. 1. A detonator base cavity 11 is filled with a detonating material (not shown) and is isolated from the base cavity 13 by the base 10, but communicates with the base firing pin bore 12. A base rotor pivot bore 16 is located central to the base clutch holding boss 15, holding the rotor base pivot shaft 92 on one side. The other side of rotor 90 has a rotor cover plug pivot shaft 93 rotatably engaging a base cover 20 in a base cover plug bore 21. A biased helical rotor spring 80 has one end 81 fixed in base 10 at point 17 and its other end interfittably engaging the rotor spring slot 96 and wound in such a manner as to give rotor 90 a clockwise turning movement.

Referring now to FIGS. 3 and 4 upon removal of the fuze from the FREON atmosphere, the FREON evaporates from the O ring 300 and after about 20 minutes the ring 300 returns to its original size. In so doing,

the clutch 200 is left unsupported and disengages from the rotor 90. The partially freed rotor 90 rotates clockwise until it engages the counterweight hook cam contact surface 101. In the event that the clutch 200 does not disengage from the rotor 90 merely by the force of gravity, because it is being restrained by the frictional force between the surfaces of the clutch hole 201 and the base clutch holding boss 15, separation of the rotor and clutch teeth 91 and 202 respectively is effected by having a triangular tooth configuration on each so designed that the rotor spring will over ride the friction restraining force between the squared shaft 15 and clutch 200. Once the rotor is free to rotate, it rotates clockwise until the rotor arming cam projection 94 engages the counter weight cam contact surface 101. In this position the rotor spring 80 establishes a balancing force and resultant moment about the counterweight spring 102 causing the latter to deflect a predetermined distance. The sensitivity of the counterweight I00 being deflected by a given impulse is a function of the counterweight hook angle z The coefficients of friction between the aluminum rotor cam projection 94 and the brass counterweight hook cam surface 101, the flexibility of the counterweight spring 102, the torsional force of the helical rotor spring 80 and the coefficient friction between the rotor base pivot shaft 92 and the base 10, and between the rotor cover plug pivot shaft 93 and the cover plug 30.

Referring now to FIGS. 5 and 6, upon receiving an impulse, or a series of impulses, or if the device is given a predescribed angle of inclination, the counterweight sets up a horizontal force component which is transmitted to the counterweight spring 102 resulting in sufficient deflection to release the rotor cam projection 94 from the counterweight hook cam contact surface 101. Once the rotor 90 is released, after being armed, it will rotate clockwise past the firing pin lock 40. At this point in the sequence of operation the firing pin lock 40 rotates in a counter clockwise direction, thus releasing the firing pin 50, which until this time had been retained by the D shaft 43 portion of the firing pin lock 40. The firing pin 50 is thus driven by the firing pin spring 60 intothe detonator base cavity 11 into a detonator or explosive mix (not shown), thus producing the desired end results.

FIGS. 7 and 8 show the circular, radial toothed configuration of the clutch 90, the triangular shape of the clutch teeth 202, the squared base boss 15 and axially aligned rotor base shaft 92.

From the above description it will be evident that the invention provides a mechanical anti-disturbance device which may be safely dispersed, will automatically arm itself in 20 or 30 minutes after evaporation of FREON liquid, which because of simplicity of design has only a limited number of component parts, is reliable at a predetermined sensitivity level, is small of size, approximately 0.2 of a cubic inch, light in weight and independent of any battery for a power source.

I wish it to be understood that I do not desire to be limited to the exact detail of construction shown and described for obvious modifications will occur to a person skilled in the art.

What is claimed is:

1. An anti-disturbance fuze for detecting the presence of intruders comprising:

a housing which includes;

a base having a main base cavity, a detonator cavity partially isolated from said main cavity, and a firing pin bore communicating with said detonator cavity and said main base cavity;

a base cover for operatively positioning said arming delay means interfitably engaging said base;

an arming delay means operatively positioned in said housing for holding said fuze in a safe mode which includes;

a clutch slidably positioned on said base in said main cavity;

6 an O ring intermediate to said clutch and said contacting said first arming cam projection surface,

housing for operatively positioning said clutch and holding said device in an armed mode. and Of a materia WhiCh expands When s d 4. A device as recited in claim 3 further including a in a fl d an Contracts when Said fluid is not counterweight spring cantilever, connected on one end P 5 to said counterweight.

a vaporizable fluid immersing said O ring;

a rotor held adjacent to said clutch when said O is expanded and releasable by said clutch when unexpanded, having a first arming cam projection surface and a second firing pin lock release cam surface;

a biased rotor spring for providing a rotational force to said rotor;

a disturbance sensing means proximate to said arming delay means for detecting impulses to said fuze;

5. A device as recited in claim 4 wherein said firing means comprises:

a firing pin slidably positioned in said firing pin bore;

a firing pin plug fixed in said firing pin bore;

a biased firing pin spring intermediate to said firing pin and said firing pin plug for providing an accelerating force to said firing pin; and

a firing pin lock rotatably mounted in said housing for releasing said firing pin when said device is suband ject to an impulse causing-said counterweight to a firing means operatively connected to said sensing move away from sald. first f g cam Prolecuon means f fi i f a detonaton surface thereby permitting said biased rotor to ro- 2. A device as recited in claim 1 wherein said O tate and Rermiliting Said firing p lock to P 531d ring material is SILICONE rubber and said vaporizable Second firing P lock release Cam Stiff-ace. 50 h fluid is FREON. said firing pin lock no longer restrains said firing 3. A device as recited in claim 2 wherein said distur- P permitting Said biased firing P to travel 0- bance sensing means comprises: ward said detonator and impacting thereon.

a pendulous mass, positioned adjacent to said rotor, 

1. An anti-disturbance fuze for detecting the presence of intruders comprising: a housing which includes; a base having a main base cavity, a detonator cavity partially isolated from said main cavity, and a firing pin bore communicating with said detonator cavity and said main base cavity; a base cover for operatively positioning said arming delay means interfitably engaging said base; an arming delay means operatively positioned in said housing for holding said fuze in a safe mode which includes; a clutch slidably positioned on said base in said main cavity; an ''''O'''' ring intermediate to said clutch and said housing for operatively positioning said clutch and of a material which expands when immersed in a fluid and contracts when said fluid is not present; a vaporizable fluid immersing said ''''O'''' ring; a rotor held adjacent to said clutch when said ''''O'''' is expanded and releasable by said clutch when unexpanded, having a first arming cam projection surface and a second firing pin lock release cam surface; a biased rotor spring for providing a rotational force to said rotor; a disturbance sensing means proximate to said arming delay means for detecting impulses to said fuze; and a firing means operatively connected to said sensing means for firing of a detonator.
 2. A device as recited in claim 1 wherein said ''''O'''' ring material is SILICONE rubber and said vaporizable fluid is FREON.
 3. A device as recited in claim 2 wherein said disturbance sensing means comprises: a pendulous mass, positioned adjacent to said rotor, contacting said first arming cam projection surface, and holding sAid device in an armed mode.
 4. A device as recited in claim 3 further including a counterweight spring cantilever, connected on one end to said counterweight.
 5. A device as recited in claim 4 wherein said firing means comprises: a firing pin slidably positioned in said firing pin bore; a firing pin plug fixed in said firing pin bore; a biased firing pin spring intermediate to said firing pin and said firing pin plug for providing an accelerating force to said firing pin; and a firing pin lock rotatably mounted in said housing for releasing said firing pin when said device is subject to an impulse causing said counterweight to move away from said first arming cam projection surface thereby permitting said biased rotor to rotate, and permitting said firing pin lock to pass said second firing pin lock release cam surface so that said firing pin lock no longer restrains said firing pin, permitting said biased firing pin to travel toward said detonator and impacting thereon. 